Rising food prices are due to overpopulation, Britain's Prince Philip said in a rare documentary on Queen Elizabeth II's husband of 60 years, to be broadcast from Monday.
"The food prices are going up -- everyone thinks it's to do with not enough food, but it's really that demand is too great, too many people," said the outspoken royal, 86, according to Sunday newspapers.
"It's a little embarrassing for everybody, no one quite knows how to handle it."
The monarch's consort is expected to keep out of political affairs.
The Duke of Edinburgh agreed to cooperate with a fly-on-the-wall documentary because he was worried about his gaffe-prone and grumpy image and wanted a "legacy" film about his life, said The Mail on Sunday.
"The Duke: A Portrait of Prince Philip" is a two-part documentary to be aired on Monday and Tuesday on ITV television, which has been given unparalleled access to the prince, who rarely steps out of Queen Elizabeth's shadow and into the spotlight alone.
The programme will portray Prince Philip as a maverick environmental campaigner, speaking out on issues including conservation, over-population and animal welfare.
The prince reflects on bringing together conservationists and religious leaders -- including the pope -- to help spread his environmental message.
"It seemed to me that most religions attributed the world to some special creation and I said, 'Well look, if you believe God created the world you ought to take an interest in its well-being."
The programme includes archive footage and events up to the recent state visit of French President Nicolas Sarkozy and his new wife Carla Bruni.